This disclosure relates, in general, to electrical watthour meters and, more specifically, to watthour meter socket adapters.
In the electric utility industry, plug-in, socket-type watthour meters are commonly employed to measure electrical power consumption at a residential or commercial building establishment. A cabinet is typically mounted on an outside wall of the residence or building and contains a meter socket having pairs of line and load contacts which are connected to electric power line conductors extending from the utility power network and electric load conductors connected to the residential or building establishment power distribution network. The contacts receive blade terminals on a plug-in watthour meter to complete an electric circuit through the meter between the line and load terminals mounted in the cabinet for the measurement of electrical power consumption.
S-type, socket-type, plug-in watthour meters have replaced older A base bottom connected meters which were formed of a single piece housing in which the watthour meter was fixedly mounted along with compression terminals which provide connection to the utility power lines and the building load distribution network.
In an installation involving an A-type bottom connected meter, an A to S socket adapter is used to allow a new S-type watthour meter to be installed. The socket type meter has outwardly extending blade terminals which are insertable into the jaw contacts in the cabinet of a S-type meter socket. The socket adapter includes its own set of female jaw contacts which receive the male blade terminals of the S-type plug-in, socket-type meter.
A socket extender adapter used to convert a ringless style socket to a ring-type socket has a similar arrangement of contacts and terminals to plug-in to a socket and to receive an S-type, plug-in, socket-type meter.
While it is typical for a watthour meter, once it is installed in a socket or socket and socket adapter, to remain in service for many years, it is still necessary for such meters to be removed for repair or replacement from time to time as well as to temporarily disconnect electrical service to a particular customer. During the installation and removal of the watthour meter from the socket or socket adapter, the electric power line terminals in the socket or socket adapter remain connected to the electric utility power line conductors and carry potential. The utility employee installing or removing the watthour meter may inadvertently touch such contacts thereby raising the possibility of injury. Furthermore, an inadvertent short across the contacts caused by a tool contacting the contacts or a full fault caused by a 90.degree offset insertion of the meter can cause a spark or flash which could damage the watthour meter installation as well as posing a significant risk of injury to the utility employee.
Various flash covers or shields have been devised as separate attachments to cover a portion of the jaw contacts in a watthour meter socket or socket adapter. The latest flash covers or shields have been designed for simplified installation through a snap-on connection with the socket adapter base or housing.
However, there is a tendency for such flash covers or shields to separate from the socket adapter base or housing when a watthour meter is pulled upward during separation from the socket adapter.
In A to S socket adapters and ring style socket adapter extenders, two mating mounting flanges on the outer portion of the socket adapter housing and the watthour meter base are locked together by a ring lock clip or sealing ring.
One type of a ring lock clip or sealing ring has housings attached to opposite free ends of an annular band. A threaded screw is captively mounted in a housing and is threadingly engageable with the opposite housing to tighten or loosen the annular ring about the mating mounting flanges to lock the two mounting flanges together. Apertures or slots formed in the fastener, and/or the housings of the annular ring receive a wire seal or plastic pad lock after the ring lock clip has been mounted about the mating mounting flanges of a watthour meter and meter socket cover or about a watthour meter and the socket adapter extender.
A to S socket adapters also include a removable cover which is mountable over the terminals in a bottom portion of the socket adapter. A metal clip is typically mounted in the socket adapter base or front housing and is insertable through a slot in the cover to receive a wire seal or plastic pad lock to provide anti-tampering indications for the cover. The cover itself typically snaps into the socket adapter base or front housing.
Electrical overvoltage surge protection is typically provided in such socket adapters or socket adapter extenders by means of a surge guard mounted in the socket adapter housing and connected through a mounting bolt to the socket adapter hanger. Portions of the surge guard extend into the socket adapter mounting flange or rim so as to engage a ground tab on the watthour meter base to electrically ground the watthour meter base through the surge guard to the socket adapter hanger and the surrounding socket mounting surface or closure.